I tried building a similar air purifier in Belgium last year and I've never been able to source the parts at a similar cost.
Experiments on a $50 DIY air purifier that takes 30s to assemble
81–90 of 149 posts
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#82I tried building a similar air purifier in Belgium last year and I've never been able to source the parts at a similar cost.
Same problem for The Netherlands here. I just want to put a hepa filter on a fan, but unfortunately I can only find hepa filters for vacuum cleaners or existing air purifiers.
If anybody has a link for where to buy a regular square/rectangle hepa filter, that would be great.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#83Another way to do it is to bubble the air through water. As a kid, we did an experiment where a cigarette was "smoked" by attaching a tube to the cigarette filter, the tube exited at the bottom of a flask filled with water, and a pump would suck the air from the top of the flask. It didn't take long before the water would turn black. Quite a turnoff for wannabee smokers, which was the obvious point of the experiment.…
Another way to do it is to bubble the air through water. As a kid, we did an experiment where a cigarette was "smoked" by attaching a tube to the cigarette filter, the tube exited at the bottom of a flask filled with water, and a pump would suck the air from the top of the flask.
"We built a bong and discovered that bong water is really nasty."
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#84I did a bit of experimentation with different filters for a DIY build like that.
Setup: I tried out a bunch of different air filters in a medium-sized apartment. Two objectives: how fast PM2.5 is removed, and down to what level can it bring down PM2.5.
From worst to best:
* Nordic Pure 20x20x4M15+C MERV 15 - the carbon layer absolutely kills airflow, doesn't work
* Filtrete 20x20x1, AC Furnace Air Filter, MPR 2800 / MERV 14 - works okay
* Nordic Pure 20x20x4 - works well
* Lennox Corporation X7935 20X20X5 MERV 16 - works the best. This thing is an absolute beast in terms of filtration performance; significantly lower steady-state PM2.5 readings during the California fires.
Test equipment: Awair and Plume Flow v2.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#85I used a 20x20x1 taped to a box fan for over a year as an air purifier because I had ferrets, and ferrets leave a particular odor floating about most of the time.
I didn't want to use an odor-removing filter with charcoal on my furnace because they're super thick and put strain on the motor, and I don't care about the box fan.
It worked really well, probably the biggest challenge was securing the filter to the fan: I put my filter on the "out" side of the fan, and it was really hard to keep it attached. Duct tape and the like actually often would fail, and air would just start moving around the filter. For good airflow through the filter I really had to give the air little other choice.
I'm curious if it would've worked just as well had I filtered the air on the "in" side of the box fan... keeping it attached would've been much easier, but I'm not sure if there's any forces that would make "pushing" air through the filter work better than "pulling" air through the filter.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#86These boxfan + hepa filters seem pretty affordable, but seem to have a really strange physical footprint. Do SUV cabin fans not push enough CFM to be effective? https://www.rockauto.com/en/moreinfo.php?pk=10863244&cc=1502...
This paired with a filter seems like it would do the job, and based on the enclosure you might be able to have a smaller footprint. No CFM data though.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#87I used a 20x20x1 taped to a box fan for over a year as an air purifier because I had ferrets, and ferrets leave a particular odor floating about most of the time. I didn't want to use an odor-removing filter with charcoal on my furnace because they're super thick and put strain on the motor, and I don't care about the box fan. It worked really well, probably the biggest challenge was securing the filter to the fan: I…
Personally I'd do the filter on the input side of the fan. They're designed to be pretty free flowing to begin with, since they're intended to be on the input side of the furnace blower. It would also keep the fan itself a bit cleaner. Suction is almost sufficient by itself to keep the filter in place.
FWIW, Alton Brown made a jerky dryer using a similar technique, and he used bungee cords to hold the filters to the box fan. That's probably less hassle than duct tape.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#88These boxfan + hepa filters seem pretty affordable, but seem to have a really strange physical footprint. Do SUV cabin fans not push enough CFM to be effective? https://www.rockauto.com/en/moreinfo.php?pk=10863244&cc=1502... This paired with a filter seems like it would do the job, and based on the enclosure you might be able to have a smaller footprint. No CFM data though.
I think box fans are used because that's what people already have around. When wildfires rendered our air here in the PNW unbreathable last September a lot of folks were scrambling for something that would work quickly. Waiting around for an SUV cabin fan to arrive and then trying to figure out an enclosure made that a non-starter.
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#89From "Better Box Fan Air Purifier" https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-a... : > Air purifiers can be expensive and you've probably seen articles recommending to just put a 20" x 20" x 1" furnace filter on a cheap 20" box fan and POOF! instant cleaner air for not a lot of money. It really does clean the air pretty cheap. > There's a problem with this though. These fans weren't designed to be run…
> we'll use two 20x25x1 filters which increases the filter surface area over 250%.
That seems like an overly complicated first attempt, why not just switch to a 20x20x4?
Re: Experiments on a $50 DIY air purifier that takes 30s to assemble
#90The only downside of the DIY route is the noise. Most box fans that I've seen are very noisy relative to "real" air cleaners/purifiers. I've used a box fan plus furnace filter for years to deal with cat litter dust. Since the particles I want to filter are quite large, I can get away with using a fairly cheap furnace filter. The nice thing about this is that it's really easy to scale it to your requirements. To deal…
I'm using Vornado fan with 2 16x20x1 merv 11 filters from lowes (2 to make triangle). And in lowest speed it's very quiet. I have commercial air cleaner and my diy is way cheaper to run and as quiet. https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-a... - like this.
I swear I came across that post at one point - it looks very familiar!
I really want to do this because 20x25x1 filters are a LOT easier to find (where I am anyway) than 20x20x1 filters. The only obstacle is that the resulting unit ends up taking a lot more space, and that's at a bit of a premium in the place I need it.
If I move the litter boxes to somewhere with more space I will definitely switch to this design.